The objective of the proposed research and training plan is to develop an independent translational research career focused on the prevention of pediatric obesity. Dr. Sabina Gesell's long-term career goal is to build an expertise in the measurement of social networks and their utility in spreading health behaviors with the purpose of developing population-based interventions that (1) target critical windows of human development associated with obesity later in life, and (2) are sustainable. The institutional environment and commitment to the candidate are ideal: Department Chair, Vice Chair for Research Affairs in Pediatrics, and Vice Chair for Faculty Development in Pediatrics are all firmly committed to her success and providing the necessary protected time and direction to attain the goals outlined in this proposal. Division Director and Primary Mentor, Dr. Shari Barkin has committed to actively supporting her through mentoring and resources to ensure project success and career development into a productive independent researcher. Vanderbilt's CTSA infrastructure to develop a successful T2 research program is unparalleled. The proposed career development plan is focused on gaining knowledge and advanced skills in social network analysis, modern longitudinal data analytic techniques, cost-effectiveness analyses, and ethics and methods of community-engaged research through (1) rigorous conduct of the research plan, (2) intensive research mentorship, (3) advanced coursework, (4) independent study, (5) faculty research seminars and working groups, and (6) national meetings. The associated research project is a social network intervention designed to facilitate healthy weight gain during pregnancy. It is estimated that 45% of US women gain in excess of the Institute of Medicine (IOM) clinical guidelines for weight gain during pregnancy. Excessive gestational weight gain is associated with gestational diabetes mellitus, pregnancy-related hypertension, complications through labor and delivery, infant macrosomia, childhood obesity, and persistent maternal obesity postpartum. Both the IOM and the Agency for Healthcare Research and Quality (AHRQ) have identified the lack of effective gestational weight gain interventions as a major research gap. The goals of the proposed research project are (1) To refine a culturally-tailored social network intervention for Latina women to prevent excessive weight gain during pregnancy; (2) To conduct a randomized controlled trial with more than 120 pregnant Latinas (e16 years old) to test the effect of this community-based intervention on gestational weight gain and likelihood of gaining within IOM target ranges; and (3) To examine the extent to which healthy lifestyle behaviors during pregnancy (nutrition, physical activity) are spread through new social ties. The study will build on the trust and substantive community relationships already developed by this research team, as well as their extensive preliminary research that supports the proposed approach. The training and research will support a successful R01.